In order to study the law of crack initiation， growth and evolution of explosives under weak load. The numerical simulation of crack initiation and evolution of explosives was carried out by using the material model considering the phenomena of tensile and compressive anisotropy with strain rate effect. The numerical results are in good agreement with the test data， and the applicability of the numerical model is verified. The typical characteristic images of crack generation and evolution of explosives were obtained through a series of numerical simulations， and the effects of initial crack size， loading rate and loading position on the crack propagation process of explosives were also analyzed， which can provide reference for the analysis of damage and fracture process as well as the dynamic response of explosives.